Transcript

Norman Swan: For the first time research has conclusively shown that treating a common form of high blood pressure, hypertension, extends people’s lives significantly. Professor John Kostis is Chair of Medicine and founding director of the Cardiovascular Institute at the Robert Wood Johnson School of Medicine in New Jersey.

John Kostis: This is a follow up of a randomised trial that we carried out in the late ‘80s. The study was to establish whether treating people with isolated systolic hypertension, that’s when the diastolic pressure was normal while the systolic was high would result in improved outcomes.

Norman Swan: And just before you go on, how common is it for people who have got high blood pressure for it just to be the top figure that’s high and how high does it have to be?

John Kostis: Depending on the age, it is rare in young people and after the age of 65 it is maybe up to 90% of hypertension.

Norman Swan: And how high does it have to be to qualify as high blood pressure?

John Kostis: At that time we would have classified it at 160 and above, now it is 140 and above.

Norman Swan: And what outcomes were you looking for then?

John Kostis: The primary outcome was fatal or non-fatal stroke.

Norman Swan: Which is the main risk for high blood pressure in addition to heart attack.

John Kostis: Hypertension does five bad things that the patients don’t like. One is a stroke, the other is heart attack, the other is heart failure, the other is death and the last is dialysis – renal failure.

Norman Swan: And what did you find in that first study?

John Kostis: We found in that study which was randomised, double blind and placebo controlled, that we could prevent over an average follow-up of four and a half years one out of two heart attack admissions, one out of three strokes and one out of four heart attacks. But the effect on mortality was not statistically significant or was a minor trend.

Norman Swan: So in other words it was an act of faith that you were saving lives?

John Kostis: No we did not test the hypothesis about lives, we only wanted to prove, at that time there was a fear that lowering the diastolic blood pressure too much, the average as they came in was 76, rather low, if we dropped it lower people would suffer because their body was used to high blood pressure and perfusion of the coronary arteries in the brain would decrease by dropping it below 76, which was the average at that time.

Norman Swan: Just to explain a bit further here, you’re focussing on the high top figure but the background figure, the diastolic, the low figure, is really like the background pressure that keeps the blood essentially getting oxygen to the tissues and if you drop that the question was is the bottom going to fall out of the blood pressure market in a sense.

John Kostis: That’s the point and would the participants get strokes or would they have cognitive decline, even if they didn’t have a stroke maybe they wouldn’t be able to drive for example. So this was the hypothesis that we tested and this was the first time that this hypothesis was tested and now we know that treating that hypertension accrues big benefit.

Norman Swan: Just to recap, we’re talking about what’s called systolic hypertension. Your systolic blood pressure is the top figure that your doctor or nurse measures. So what they showed in the first report of that trial was that the hypothetical risks of reducing systolic high blood pressure did not exist and the benefits were large. But what you and I care about is whether we live longer in good health and this latest study followed the survivors and indeed found that as time went by, those who had been on the placebo died sooner than those who’d been on the active blood pressure lowering treatment.

John Kostis: It corresponds to about one day longer for a month of being treated.

Norman Swan: That’s not a bad equation.

John Kostis: It’s not a bad equation especially if you consider that these people as we started were 72 years old average. The oldest was 96 so it is not a bad calculus, but also the other aspect that we want to highlight is the legacy effect.

Norman Swan: At first sight the legacy effect is more of interest to researchers than mere mortals like you and me, but it does actually tell you something important: When people on a trial finish and the active treatment’s been shown to work, usually those on placebo are offered the chance to go on to the real medicine. And many choose to do so.

The legacy effect is that when you follow both groups for many years, those who were initially recruited to the real medication continue to do better than those who’d been on placebo even though they’re now on treatment.

It’s basically a message about getting on to treatment sooner rather than later. The best explanation for the legacy effect according to John Kostis is that while on the trial the blood pressure lowering medications prevented many people from having their first heart attack.

John Kostis: But it is the second heart attack that kills you.

Norman Swan: So the group that didn’t get treated have already had their first heart attack or stroke?

John Kostis: That’s right therefore the non-fatalist difference becomes mortality difference later on. The other explanation is a little more subtle than that. That is if you treat somebody you prevent the structural and functional abnormalities that the risk factor imparts on the arteries. Therefore you may not know anything, you may not have a non-fatal event but your arterial system is damaged by hypercholesterolaemia or hypertension for five years more than the ones who got treated.

Norman Swan: And what about harms?

John Kostis: The harm if you want to call it harm is the competing risk, that is if you live let’s say a year longer than otherwise, two brothers, one lives a year longer because he gets treatment, identical twins. One dies at 75 the other one lives an extra year. During that year he has the risk of dying from cancer, or from Alzheimer’s, or kidney disease, or pulmonary disease – they are the common ones. And that’s called a competing risk. Therefore we found as expected an increase in non-cardio vascular deaths.

Norman Swan: That’s a relative phenomenon, you’ve reduced the statistics for heart disease therefore the other causes come to the fore.

John Kostis: Since you live longer.

Norman Swan: And what about side effects?

John Kostis: Our point was to look at the net benefit of anti-hypertension therapy and there are many anti-hypertension agents. I don’t know how many preparations are approved in Australia, but in the US there are over 120. There’s always a discussion from each pharmaceutical house that says ours is better for X, Y and Z, our main point is treating hypertension.

Norman Swan: As you say there’s a huge debate amongst the medical community usually influenced by marketing from the pharmaceutical industry about old versus new drugs. I mean a few years ago a group in Houston found that the old drugs were at least as good as the new ones, maybe even a bit better.

John Kostis: You’re from Australia -- there’s a group of us, that is the George Institute in Australia, well they’re my friends and we are a group who call ourselves the triallists and we have published a few papers in The Lancet stating in essence that what counts is dropping blood pressure and if the choice of drug makes a difference it’s trivial compared to how well you drop your blood pressure.

Norman Swan: And the bottom line Dr Kostis what is the message for consumers listening?

John Kostis: My message is to treat your blood pressure early, don’t wait until you’re 70 or 80 to treat it. The message is treat the risk factors early. Do you know poliomyelitis? You don’t have any, there’s no poliomyelitis and you’re not afraid of it, but I’m sure you know and you may even have family members, aunts or uncles who had heart attacks or strokes -- why aren’t we afraid of poliomyelitis? Poliomyelitis is a very benign disease, I was never vaccinated myself but I’m sure I got it when I was growing up in Greece. Polio usually gives you a little diarrhoea, and it’s rare that it gives you paralytic polio when you treat with iron lungs. Now we are not afraid, neither you nor even I are not afraid of polio because we didn’t eliminate it through iron lungs, but we’ve eliminated it by eliminating all polio, not paralytic polio.

On the other hand for cardiology we give iron stents instead of eliminating the way polio is and in my view if we start treating early you prevent a disease that is atherosclerosis, not the heart attack -- it’s too late already. Coronary disease starts let’s say in your 40s and you have a heart attack in your 70s and I don’t know you probably have it in Australia, the guidelines are if you have a heart attack we have to open the artery within 90 minutes otherwise we get a black mark -- right? Well that is the last half second we start running, for 20 years we do nothing and the last 90 minutes we’re running. It’s totally, totally wrong. In my view we should start treatment early, eliminate the risk factors as much as we can. Therefore prevent the disease not the event.

Norman Swan: Dr John Kostis is Chair of Medicine and founding director of the Cardiovascular Institute at the Robert Wood Johnson School of Medicine in New Jersey.

Credits

Comments (1)

Campbell Bearlin :

16 Feb 2012 5:35:38pm

On the morning of this broadcast, if I recall corectly, Norman spoke with Fran K re this program and mention was made of differences in blood pressure in the arms of the same person at the same time. One assumes this topic was not broadcast. Is it to be discussed again? Where can one find reference to this fascinating and apparently important subject?